The invention relates to a method and apparatus for heating an elongated article. In another aspect the invention relates to a method and apparatus for fusing at least a portion of the synthetic filaments in a non-woven fabric by infrared radiation.
Frequently it is desirable to heat an elongated article. For example, a nonwoven fabric made from synthetic fibers, such as polypropylene fibers is often heated to fuse a portion of the fibers together in order to give the resulting fabric greater strength and dimensional stability. It has recently been found that fusing the filaments of a nonwoven fabric using infrared heaters provides an excellent product; however, it is difficult to start and stop such an infrared heating system without producing some fabric which is either fused too little or too much.
If a conveyor transporting the nonwoven fabric is started after the infrared heaters are energized, it is difficult to prevent the heat from overfusing or actually burning holes in the fabric. On the other hand, if the conveyor is started before the heaters are energized, then a segment of fabric is produced which is not adequately fused. Thus, there is a need for method apparatus for heating an elongated article, such as a nonwoven fabric of synthetic filaments using infrared heat, in which the heating system can be started and stopped without producing segments of the fabric which are subjected to an undesirable degree of heat.
It is an object of the invention to heat an elongated article.
Another object of the invention is to heat an elongated article using infrared heat.
Another object of the invention is to fuse together the filaments of a nonwoven fabric using infrared heat.
Another object of the invention is to start and stop an infrared heating system used for fusing together the filaments of a nonwoven fabric without producing some fabric which is either fused too little or too much.